FIGURE 5.

Mutation of conserved tyrosine residues affects U1-SL4 binding by SF3A1. (A) Alignment of SF3A1-UBL domains from human, mouse, zebrafish, flies, and worms. In the aligned sequences, a dot indicates the presence of an identical residue and a tilde indicates a gap. (B) Western analysis using anti-SF3A1 primary antibody demonstrating expression of SF3A1-WT and point-mutants Y772C, Y773C, and R511Q in CFE reactions. The expression of mutant proteins relative to WT, normalized to α-Tubulin, is graphed below the western blot. (C) Crosslinking of WT and mutant SF3A1 proteins to ³²P-U1-SL4-WT and -M10h RNAs. Crosslinking efficiency, relative to WT SF3A1, is represented in the graph below (* = P < 0.05, Student's t-test). For gels, arrows indicate specific crosslinked products and asterisks indicate nonspecific products that were seen in reactions containing the EV control.